JP4222725B2 - Ballpoint pen - Google Patents

Description

  According to the present invention, the writing ball at the tip of the pen tip is prevented from coming off in a state having a gap of an appropriate size for securing the ink flow path at the tip, and the writing ball at the pen point is always pressed with an elastic body. In order to improve the ballpoint pen with the ball valve mechanism at the tip, especially ball play, writing performance, impact resistance, vibration blurring of oil-based or water-based ballpoint pens or knock-type ballpoint pens with medium viscosity, etc. It is an improvement regarding the resolution of the problem.

  Conventionally, in a ballpoint pen-type writing instrument, a so-called oil-based ballpoint pen in which high-viscosity ink (about 10,000 cp) containing a higher alcohol solvent as a main solvent is directly incorporated in an ink storage tube, or a very low viscosity (2 To 3 cp) of so-called water-based ballpoint pens stored in a fiber bundle core called batting, and neutral ballpoint pens having an intermediate property between oil and water. Oil-based ballpoint pens are high in viscosity and have a heavy writing feel, lots of stickiness, and ink is stored directly, so that if air enters the tip, a trouble of backflow tends to occur. Water-based ballpoint pens have drawbacks such that the remaining amount of ink cannot be confirmed, they are likely to bleed on the paper surface, members such as batting and relay cores do not expel all ink, have a short life, and have a thick shaft. In order to solve these problems, the neutral ballpoint pen has been solved for backflow by a backflow prevention mechanism such as a ball valve. The present applicant has also proposed an invention of a neutral ballpoint pen of a type in which a writing ball is always pressed inside the pen tip with a weak load, but when used in an actual writing instrument, the following problems have been found, A need for improvement has arisen.

  In the type of ballpoint pen that presses the writing ball with the internal elastic body, the ball pops out when writing, even though the receiving seat and tip are worn by the ball and ink still remains. May cause problems that cannot be written. In particular, when the ink colorant is a pigment type ink in which solid fine powder is dispersed, or in the case of an aqueous type ink based on water with poor lubricity, or even if it is oily, the viscosity of the ink is medium. In the case of an ink having a degree (10 to 5000 cp at 25 ° C.), these problems are particularly likely to occur because the ink film is easily cut off due to wear due to solid content or rotation. As countermeasures for these, measures have been taken in which the material of the ball or chip holder is changed to a material such as high hardness stainless steel. In that case, however, the processing of the chip holder becomes difficult in proportion to the hardness. It has a drawback that it becomes stubborn and expensive. When improved with ink, these defects can be alleviated if a large amount of lubricant is added to the ink. However, the lubricant makes the ink more likely to bleed onto the paper surface, and the surface tension of the ink decreases, causing the pen to drop. It was found that the problem of direct current that the ink leaks from the pen tip tends to occur when it is easy to get wet first and face down, so that improvement with easy ink is difficult.

  Also, ballpoint pens that use volatile ink will prevent the ink from volatilizing when not writing, etc., or if the ink is trapped or damaged due to a drop or other impact, the ink may flow backward or In order to prevent the so-called direct current from dripping from the tip of the pen, a countermeasure is provided by providing an elastic body that constantly presses the writing ball. However, the ball jumping occurred in the case of internal wear due to writing or severe cases. In the case of a knock-type ballpoint pen, the problem of being easily shocked when storing the refill as a cursive body and causing the ball to fly is more severe, and as the writing ball diameter increases, it is advantageous in terms of wear, but small Due to the impact rather than the case of the writing ball diameter, a problem of scumming due to air entrainment from the tip has occurred. In order to prevent these problems, measures have been devised to insert rubber or springs into the refill and shaft for the purpose of shock absorption. However, this causes the shock absorption rubber to bend during writing and cause the pen tip to move back and forth. There are also problems that are difficult to write, and there is a problem that the cost increases because the number of parts increases and it is necessary to devise fixing.

  In particular, so-called neutral ballpoint pens using medium viscosity ink between oil-based ballpoint pens and water-based ballpoint pens are likely to cause these problems, and although they are somewhat incomplete, they are put on the market in recognition of other advantages. Although some ballpoint pens that have improved these problems have been invented, the problem of wear inside the pen nib and the problem of sag caused by impact resistance have been increased. There is a need to improve it to an effective solution that solves all the new problems caused by the demand for fine characters.

The present invention is mainly aimed at improving a so-called ball-point pen type writing instrument in which a ball serving as a writing part protrudes from the tip in a popular pen tip and is loosely fitted and is loosely fitted. This is related to the improvement of ballpoint pens with inks of viscosity, and the writing quality at the time of writing can be secured from the beginning, and the writing becomes impossible and writing becomes impossible before the end of the life of the pen body This is the first purpose.

  Furthermore, by solving the problem of blurring due to each writing ball diameter and the problem of blurring and ball skipping due to return impact in the case of a knock type without sacrificing ballpoint pen manufacturability or pen performance, ink with a special formulation It is to solve the problem of providing an inexpensive and high-performance writing instrument without requiring an advanced mechanism.

The ballpoint pen of the present invention devised in order to solve the above-mentioned problems is prevented from coming off so that a ball serving as a writing part can be exposed to the outside at the tip, and an ink is contained in the ink containing tube. Built in. This ink passes through an ink flow path such as a plurality of channel grooves that are appropriately sized inside the pen nib, horizontal play, and vertical play that allows the ball to move so that ink can be drawn up and down. It is configured such that it can be led out to the outside on a paper which can be rotated and serves as a writing part. The loosely fitted ball is prevented from coming off by a front caulking due to plastic deformation or the like and a rear receiving seat while being freely rotatable. The ball is prevented from coming off by stable caulking by optimizing the ball exit, caulking inner diameter, and caulking outer diameter, for example, by caulking slightly inside the caulking part until it comes into contact with the ball during caulking. If the sealing surface is formed into a shape having a certain width over the entire circumference with R substantially the same as the ball, the problem of direct current can be further solved. In addition, it is effective for the problem of wear if the vertical backlash is ensured and at the same time a receiving seat having an R which is substantially equivalent to the ball is provided as a receiving surface on the rear side in the axial direction of the ball.

That is, the first gist of the present invention that brings about such an effect is that the tip end portion of the shaft has a tip hole from which the writing portion can protrude, and the rear end has a knock bar serving as a protruding pressing portion, which protrudes from the tip. rotatably loosely fitted balls in state, the tip end has been moved regulations retracted before each by receiving seat to the rear side by the crimping, an ink hole for deriving ink from the rear side of the interior a nib having an ink viscosity at room temperature (23 ° C.) is configured with an ink containing tube which directly hoarding viscosity inks called ranges 5000cp from 10 cp, a plurality of grooves for communicating the receiving seat and the ink hole It has a channel groove that does not penetrate in the longitudinal direction, and an elastic body that is placed so that it cannot be pulled out so that the ball at the tip is always pressed directly or between the movable members, and becomes a writing body inside the shaft. Before and after refill To be able to accommodate the at the knock-type ball-point pen,
The relational expression: 20 · W <P <75 · W is satisfied between the projected area W (mm ² ) of the writing ball diameter and the pressing force P (g) of the elastic body in the nib , and the refill is always performed. It is configured to be urged rearward by a return spring, and there is a relational expression between the ball pressing force P (g) in the pen tip, the pressing force S (g) of the return spring, and the refill weight R (g). : A ballpoint pen characterized in that 50 · R <S <(50 · R + 20 · P) is satisfied .

Next , the second gist of the present invention has a so-called double knock type knock mechanism in which the knock bar is pressed to allow the writing body to project by allowing the writing body to protrude, and the knock bar can be pressed again to store the writing body. In the knock-type writing instrument, the rotor that contacts the refill or the rear of the refill moves while rotating during the refill movement distance L from when the writing state protrudes to when the non-writing is stored. 2. A ballpoint pen as set forth in claim 1, wherein a part of the impact caused by the spring pressing force is converted into a rotational motion at a predetermined angle θ, and the relational expressions are 5 mm <L <10 mm and 40 degrees <θ <160 degrees. It is in.

Further, the third gist of the present invention has a so-called double knock type knock mechanism in which the knock bar is pressed to allow the writing body to project by allowing the writing body to protrude, and the knock bar can be pressed again to store the writing body. In the knock type writing instrument, the return spring during retraction moves while the rotor in contact with the refill or the back of the refill moves during the refill movement distance L from when the writing state protrudes to when the non-writing is stored. The ballpoint pen according to the first aspect, wherein a part of the impact caused by the pressing force is converted into a rotational motion at a predetermined angle θ, and a relational expression: 5 mm <L <10 mm and 40 degrees <θ <160 degrees. is there.

Furthermore, the fourth gist of the present invention is that a clip having elasticity is provided on the outside of the shaft cylinder, and a writing body is projected so as to be writable by an engaging portion of the clip, and the clip is lifted to put the ball-point pen on clothes. In a knock-type ballpoint pen with a so-called safety mechanism that automatically stores the refill as a cursive body, all parts that are separated from each other in the writing state behind the refill and collide with each other at the time of return are subjected to impact. Made of synthetic resin such as rubber, elastomer, plastic, etc., and at least one of the parts has an internal loss η, which is a vibration absorbing performance, of 0.02 or more, and all of the parts subjected to the impact are rigid. The ballpoint pen described in the first aspect is characterized in that it is made of a material having a rate E of 1,300 MPa or more.

The fifth aspect of the present invention has a clip having elasticity on the outside of the shaft tube, and the clip is protruded so as to be writable by an engaging portion of the clip, and the clip is used for inserting the ballpoint pen into clothes. In a knock-type ballpoint pen that has a so-called safety mechanism that automatically stores the refill as a cursive object when lifted, parts that are separated in the writing state behind the refill and collide with each other at the time of return to receive impact. All are made of synthetic resin such as rubber, elastomer, plastic, etc., and at least one of the parts is vibration absorbing performance, internal loss η is 0.02 or more, and all the parts subjected to the above impact exhibit rigidity 3. The ballpoint pen according to the second aspect, wherein the elastic modulus E is made of a material having a modulus of 1,300 MPa or more.

Further, the sixth aspect of the present invention has a clip having elasticity on the outside of the shaft tube. The clip is raised by the engaging portion of the clip so as to be writable, and the clip is lifted to put the ball-point pen on clothes. In a knock-type ballpoint pen with a so-called safety mechanism that automatically stores the refill as a cursive body, all parts that are separated from each other in the writing state behind the refill and collide with each other at the time of return are subjected to impact. Made of synthetic resin such as rubber, elastomer, plastic, etc., and at least one of the parts has an internal loss η, which is a vibration absorbing performance, of 0.02 or more, and all of the parts subjected to the impact are rigid. 4. The ballpoint pen according to the third aspect, characterized in that the rate E is made of a material of 1,300 MPa or more.

As a first means for making the present invention as described above effective, an elastic body that always urges the writing ball forward is always directly behind the writing ball or via a piece that is movable between the elastic body and the writing ball. The front of the elastic body was loosely fitted by a writing ball secured by caulking, and the back was loosely fitted by caulking at the rear end of the pen tip or an internal step of the joint component behind the pen tip. Here, relationship between the projected section W of writing ball pushing force P of (mm ²⁾ and an elastic body (g): 20 · W <has a configuration which satisfies P <75 · W. That is, since the ball diameter and the projected area are in a square relationship, the pushing force of the elastic body is set to increase in proportion to the square as the writing ball diameter increases.

  As a second means of the present invention, after satisfying the first means, a knock-type writing instrument is mounted, and the refill is always urged rearward by a return spring, the weight R of the refill, the push of the return spring The relational expression: 50 · R <S <(50 · R + 20 · P) was satisfied between the pressure S and the pressing force P of the elastic body inside the nib.

  As the third and fourth means of the present invention, the knock type shaft mechanism is a so-called double knock type (also called Kern knock type) that repeats protrusion and storage of the pen tip from the inside of the shaft only by pressing the knock bar, The knock stroke movement distance L (the dimension of the difference between the pen tip protruding state and the storage size) is defined as 5 mm <L <10 mm, which is larger than the normal 4 mm, and the return from the protruding state to the stored state. The rotation angle θ at that time was set to a large value of 40 ° <θ <160 °.

  In addition, as a means to mitigate knock impact at the time of return, first, all the parts that receive the impact at the time of return behind the refill are made of synthetic resin such as rubber, elastomer and plastic. At least one of the parts is made of a material having an internal loss η of 0.02 or more, which is a vibration absorbing performance, and an elastic modulus E that indicates rigidity of all the parts subjected to the impact is 1,300 MPa or more. In particular, a pigment-type water-based ink having an ink viscosity of 10 cp to 5000 cp at 23 ° C. ± 5 ° C., called a neutral ballpoint pen, is liable to cause backflow and direct current problems and requires a prevention mechanism. It is necessary to ensure a large flow path, and the effect of the present invention is particularly great.

  The operation of the above solution will be described above. In the improvement of the present invention, it is likely to occur in the case of a mechanism that is easy to generate with a medium-viscosity ballpoint pen, prevents blurring due to vibration, direct current, and backflow, and presses a writing ball with a weak load inside the pen tip. It is possible to ensure high performance such as blurring in the case of a strong impact and a balance of writing performance. This is particularly effective when applied products such as thin letters, bold letters, knock type, etc., which are frequently requested by users. By satisfying the relationship 20 · W <P <75 · W between the projected area W of the ball diameter and the pressing force P of the writing ball, there is no blur due to vibration, and if the pushing force is too strong, the ball is difficult to rotate. The writing performance is not deteriorated, and there is no phenomenon that the tip side is worn by writing or writing due to a drop or knock impact. Furthermore, when the knock type is used, if the return pressing load S is extremely strong, the impact force becomes large, causing problems such as scumming, and if S is too weak, knocking is not intended due to shaking or light impact when carrying. There is a problem that the pen tip protrudes and stains clothes. For the purpose of alleviating or eliminating the adverse impact of return impact, if the return spring pressing load S is also defined as 50 · R <S <(50 · R + 20 · P), the minimum return pressing force is determined by the refill weight R. By setting the load S and setting the strongest return pressing load S in proportion to the pressing load P of the writing ball in the above-mentioned pen tip, it is possible to obtain a ball pen with no problem. That is, as the refill weight is heavier, the return pressing load S needs to be increased. As the writing ball pressing load P increases, the impact resistance increases, so the return pressing load S can be increased.

  In the case of a double-knock type ballpoint pen, the amount of refill movement at the time of return is not limited to the vertical movement in the axial direction, but the amount of movement in the rotational direction using a cam also acts at the time of return, resulting in impact mitigation. It also functions as a mechanism. In the present invention, for the purpose of more effective shock resistance mitigation, the rotation angle θ is larger than that of a general object when the protrusion L of the pen tip and the movement amount L during storage are set to a large stroke amount of 5 mm or more and less than 10 mm. By setting 40 degrees <θ <160 degrees, it is stored while rotating greatly at the time of return, and effectively reduces the impact. When θ is 40 degrees or less, the movement is nearly straight and the impact value to the refill is increased, and when it is 160 degrees or more, the rotation angle in one knock becomes too large to be a practical writing instrument. If the part behind the refill is made into a shock-absorbing part, it has a more effective action, but in general, many parts with a large internal loss coefficient η indicating the degree of shock absorption are soft with no rigidity and are simply soft. The object does not satisfy the function of the shape and needs to be specially arranged as an impact absorbing member, and even the load at the time of writing is deformed, and there is a problem that the pen tip moves back and forth at the time of writing. In the present invention, if this rigidity is 1,300 MPa or more, there is rigidity that the pen tip does not move back and forth by writing pressure, and if the internal loss η is 0.02 or more, it also has shock absorption, so the parts behind the refill Are made of a synthetic resin that is rigid and has a certain level of vibration absorption, and at least one component has a high shock absorption, so that it has the effect of mitigating the impact at the time of return.

  By having such a configuration, it is possible to simultaneously satisfy the assembling property, cost, and stability of parts.

  In particular, the present invention works most effectively with a neutral ballpoint pen whose ink viscosity is lower than that of an oily ballpoint pen. As the flow rate of ink is large, it is relatively difficult to impart lubricity to the ink, and the problem of direct current, backflow and wear can be solved, and flexibility in ink design can be given. In addition, the overall performance of the pen body can be improved.

  FIGS. 1 to 5 show an example of a ballpoint pen as an embodiment of the present invention, which will be described in detail below with reference to the drawings.

  A writing ball 1 is secured to the front end of a tip 8 made of a metal such as stainless steel, brass, or white or plastic, which is a pen tip of a ballpoint pen, by a caulking 2 on the front end side and a receiving seat 6 on the rear end side. The caulking 2 forms the seal surface 5 of the writing ball 1. A writing ball 1 which is a spherical body made of ceramic, cemented carbide, stainless steel or the like is loosely fitted in the inner wall 3 so as to be rotatable in a state of having vertical back and forth. The caulking 2 is caulked with a caulking angle of 40 ° to 110 ° (preferably 50 ° to 90 °). Generally, the caulking 2 is processed by plastic deformation or a combination of plastic deformation and cutting. Yes. The chip 8 has a flow path by the ink hole 7 from the rear to the tip, and the chip 8 is further fixed to the rear ink storage tube 9 or the joint 10 between the ink storage tube 9 and the chip.

In the chip 8, a plurality of radial vertical grooves are provided for the purpose of securing an ink flow path without blocking the ink holes 7 even when the ball 1 abuts against the rear inner receiving seat 6 during writing. A channel groove 4 is provided. An elastic body that constantly biases the writing ball forward is provided behind the writing ball 1 directly or via a frame (not shown) that is movable between the elastic body 12 and the writing ball 1. With the writing ball 1 secured by the caulking 2, the rear side is loosely fitted so as not to be pulled out by caulking at the rear end of the pen tip or an internal step of the joint part behind the pen tip. Normally, when the writing pressure is about 100 g at the time of writing, the elastic body 12 bends and the ball 1 moves to the back inside the pen tip to secure an ink flow path. In addition to the operation of the backflow prevention mechanism that can block the path and prevent the ink 13 from flowing back, it is possible to simultaneously obtain the function of preventing direct current from flowing out of the pen tip when the pen is turned downward. Prior to the present invention, the pressing force of the elastic body 12 has been selected as appropriate as long as it is 80 g or less, which is a load that is weaker than the pen writing load of about 100 g. However, the elasticity exceeding the setting when the ball diameter is small is selected. When the body pressing load was set, so-called ball jumping occurred in which the ball jumped out of the pen tip due to writing wear or impact. In addition, when the writing ball diameter for bold is large, if the pressing force of the elastic body 12 is too weak, the ball 1 at the tip moves due to an impact applied when the pen body is carried, and the blockage by the valve is released. As a result, there was a problem that air was introduced from the tip and faded. Here, as a result of the inventor's investigation, the relational expression between the projected sectional area W (mm ² ) of the writing ball 1 and the pressing force P (g) of the elastic body 12 is: 20 · W <P <75 · W The knowledge that can solve the problem was obtained. Generally, it is thought that it is proportional to the weight of the writing ball 1 and the impact value G. However, since the ball moves in the ink having viscosity to the very narrow gap in the nib, the resistance in the fluid Is much larger than the relationship by weight. For example, a carbide φ0.5 ball with a high specific gravity has a very light weight of 0.00088 g, and if there is a comparative relationship with the weight of a φ1.0 ball 0.007 g, the lowest occurrence of vibration blur The pressing load P was about 5 g at φ0.5 and about 18 g at φ1.0, and did not correlate with the weight ratio.

  When the knock type writing instrument is installed, the refill is always urged rearward by the return spring 25, and when the refill is stored, an impact is applied when the refill is stored inside. The writing ball 1 moves due to the impact of the elastic body 12 on the ball valve. If the return spring 25 is set to be too weak, there are problems such as operation failure or a pen tip coming out without knocking due to impact when carrying. The minimum pressing force S of the return spring 25 can be increased by the weight R of the refill, and the pressing force S of the return spring 25 can be increased if the pressing force P of the elastic body 12 inside the nib described in the first means is strong. And the relational expression: 50 · R <S <(50 · R + 20 · P) was satisfied.

In this knock-type writing instrument, a refill having a writing portion at the tip, a return spring 25 for urging the refill, a rotor 19 abutting against the rear end surface of the refill, and a knock bar 21 protruding from the shaft tube behind the refill. Have. The knock bar 21 is pressed to cause the refill to protrude from the front part of the shaft, and at this time, the stepped portion inside the shaft or the locking portion 23 of a part such as a clip 22 attached to the shaft is rotated inside the shaft. It engages with the locking rib 20 of the child 19 to maintain the protruding state. The rotor 19 between the knock bar 21 and the front refill of the knock bar 21 and the knock bar 21 having a detent are appropriately loosely fitted so as to be interlocked with the refill by a knocking operation, and receive the shaft or clip 22 in the backward direction. The part is restricted so that it can be operated only within a predetermined knock stroke.

  When the knock type shaft mechanism is a so-called double knock type that repeats protrusion and storage of the pen tip from the inside of the tip shaft 17 only by pressing the knock bar 21, the knock bar 21 returns the impact when the refill is returned. It has a structure that weakens the impact of the refill by hitting the finger and converting it to rotational force while returning. When the medium viscosity ballpoint pen is a knock type, the stroke movement distance L of the knock shown in FIG. 5 (the state where the pen tip comes out) is shown in FIG. In many cases, the size of the difference between the size and the size at the time of storage is set to be larger than the usual 4 mm. However, if it is 10 mm or more, the knocking operation becomes large and difficult to use, and the return impact also increases. Therefore, in order to make an effective shock mitigation mechanism, this dimension is defined as 5 mm <L <10 mm, and from the protruding state The rotation angle θ at the time of return to the housed state was set to be as large as 40 ° <θ <160 °. This can further reduce the impact. In FIG. 5, reference numeral 23 denotes a clip locking portion, 24 denotes a cam portion, 26 denotes a rectilinear portion, and 27 denotes a cam protrusion. In the example shown in the figure, the rotation angle θ is θ = 180 degrees (stored state) −70 degrees ( Projecting state) = 110 degrees.

  Next, the operation of each part according to the rotation angle of the rotor will be described with reference to FIG. Hereinafter, description will be made based on the rotational angle positions (a) to (h) in the drawing.

(A) First, in the figure at the 0 ° position, when the upper leftmost state is started, the cam surface provided on the knock bar 21 and the corresponding cam surface of the rotor 19 are not in a completely coincident state, but are rotated. The protrusion 20 of the child 19 is prevented from rotating by a rectilinear portion 26 provided integrally with the cam portion 24 of the rear shaft 18.

(B) Further, in the figure at the 0 ° position, when the knock bar 21 is pressed, the rotor 19 goes straight without rotating until the cam projection 27 of the rotor 19 comes off the straight advance 26 from the straight advance 26.

(C) Next, in the figure at the position of 15 °, the cam surface of the knock bar 21 and the cam surface of the rotor 19 coincide with each other after the cam projection 27 is deviated from the front end of the rectilinear portion 26. The child is rotated by 15 °. At this time, the cam projection 27 rests on the slope of the cam portion 24 of the rear shaft 18. In this state, the pen tip protrudes from the tip of the tip shaft 17, and there is no change in operation even if the knock bar 21 is pressed further.

(D) Next, in the figure at the 45 ° position, when the hand is released from this state and the pressing of the knock bar 21 is stopped, the rotor 19 starts to move backward together with the refill by the force of the return spring 25. Since the cam projection 27 moves on the slope of the cam portion 24 of the rear shaft 18, the rotor 19 moves rearward while rotating.

(E) Next, in the figure at the 70 ° position, the rotor 19 is integrally provided with a locking projection 20 and a cam projection 27, and the clip locking portion 23 of the clip 22 catches the locking projection 20. When the locked state is established, the state where the rotation of the rotor 19 and the movement toward the rear of the shaft are stopped is maintained. At this time, the pen tip is in a writable state protruding from the tip shaft 17 by a predetermined amount.

(F) to (h) Further, in order to store the pen tip, the knock bar 21 may be pressed or the clip 22 may be lifted to release the clip. As shown in the figure, (h) 180 ° state is obtained via (f) 105 ° state and (g) 135 ° state. During this time, as described above, the cam projection 27 of the rotor 19 moves backward on the slope of the cam portion 24 of the rear shaft 18 while rotating on the slope. At this time, the refill is stored. After 180 °, the cam combination having the same configuration as this configuration is provided on the opposite side, so the change from 180 ° to 360 ° is exactly the same, and finally 360 ° = 0 °, By repeatedly pressing the knock bar 21, it is possible to repeat the pen tip protruding state and the storage state.

  In addition, when the user tries to insert it into the pocket in the protruding state, the locking mechanism is released and the storage state is satisfied. In other words, a so-called safety mechanism is provided that automatically stores the pen when it is about to be inserted into the clothes, in order to prevent the ink from seeping out and smearing the clothes when the pen body is inserted into the pocket. It becomes a safer writing instrument, and more specifically, it is provided on the locking shaft 23 provided on the tip shaft side of the elastic clip 22 protruding outside the rear shaft 18 and the rear shaft 18 or a component inside the rear shaft 18. The above-described safety effect is manifested by the configuration in which the protruding state of the refill is maintained by the locking projection 20 being locked.

  All parts subjected to impact at the time of return behind the refill are made of synthetic resin such as rubber, elastomer, plastic, etc., and at least one of the parts has an internal loss η of 0.02 or more, which is a vibration absorbing performance, And all the components which receive the said impact are comprised with the material whose elastic modulus E which shows rigidity is 1,300 Mpa or more. Polyacetal, polyethylene (medium / high grade), general polypropylene, liquid crystal polymer, and the like conform to the present invention.

Even aluminum, which is a relatively soft metal, has an internal loss η of 0.005 or less and hardly absorbs vibration. As a specific example, compared with a comparative example in which the knock part and the clip part whose internal step becomes the receiving surface of the knock bar 21 at the time of return are polybutylene terephthalate (η = 0.01, elastic modulus 2,000 MPa), The knock bar is made of a liquid crystal polymer (Vectra A950 manufactured by Polyplastics Co., Ltd .: η = about 0.06, elastic modulus 8,000 MPa) or impact-resistant polyacetal (Durin Delrin 500T: η = about 0.02 or higher, elastic modulus 1, In the example of the present invention set to 900 MPa), a significant difference in vibration absorbability was found by about 30% in the evaluation of the knock-off property of the ballpoint pen. When rubber (η = approx. 0.2, elastic modulus 900 MPa) is inserted into a part that becomes a collision part of the knock bar, or the knock bar is compared with soft polyethylene (η = 0.03, elastic modulus 1,100 MPa) The vibration absorption performance is about 50% or more, but there is no rigidity, the touch of the pen tip will dent when writing, and the function such as detent of the knock bar will not be satisfied, compression There was a concern that the rigidity would be weak and plastic deformation would occur, or that the parts had to be specially attached, resulting in a thick shaft diameter and a significant increase in cost.
(Reference: Polyplastics Co., Ltd., liquid crystal polymer “Vectra” catalog)

  According to the present invention, the front and back of the pen tip during writing that occurs when using a soft and non-rigid rubber as in the past, absorbs even a small amount of vibration when subjected to an impact to reduce the adverse effect on the refill side. Dynamic problems can be solved by making the parts more rigid to some extent, and there is no cost increase factor such as the addition of parts because the basic components themselves have vibration absorption.

  As a combination with the backflow prevention mechanism, a valve chamber is provided inside the vertical hand 10 and a spherical check ball 11 or a non-spherical piece having a tapered surface at one end is known. The effect is not limited by.

  The ink 13 used in the examples has a viscosity of 10 cp to 5000 cp at 23 ° C. ± 5 ° C. under a general shearing force, and contains 5 to 50 low volatile solvents such as glycerin and propylene glycol based on water. %, 1-20% of pigments and dyes as colorants, and various other additives such as appropriate dispersing agents, gelling agents, preservatives, surfactants and lubricants. Further, behind the ink 13, a hardly volatile grease-like follower 14 and a cup-like follower rod 15 which is solid and lighter in specific gravity or lighter in specific gravity than the ink are floated. Here, for the ink 13, an aqueous type based on water, an oil type based on a less volatile higher alcohol, an alcohol type based on a lower alcohol, and a correction liquid based on a volatile solvent such as methylcyclohexane. Among various types of inks, the same effect is exhibited even if the viscosity is a medium viscosity of 10 cp to 5,000 cp.

  If a hot-melt type tip sealant 16 that melts at 80 ° C to 200 ° C is attached to the tip for the purpose of protecting the pen tip during transportation, preventing volatilization, or preventing air entrainment, long-term storage stability can be improved. Troubles caused by transportation to the user can be prevented.

  An example of product evaluation based on an embodiment of the present invention is presented. The evaluation was a three-level evaluation of ◯ × Δ, where ◯: no problem, △: trended but usable, ×: unusable. The product used for the evaluation was a knock type medium-viscosity ballpoint pen (UMN-152) manufactured by Mitsubishi Pencil Co., Ltd., and all standard parts were used except for the comparative changes of the present invention.

  The ball diameter of the pen tip is a prototype pen tip with a current shape of φ0.5 to φ1.0.

  The writing ball pressing load P in the nib was set to be a predetermined load by changing the overall length and wire diameter of the nib elastic body (coil spring).

  The refill weight was evaluated based on the current product: 2.6 g as a standard, the entire tube made of stainless steel: 5 g, and a metal pipe tail plug added: 3 g.

  The return spring strength was set to a predetermined load by changing the overall length and wire diameter of the coil spring.

Evaluation items are 1) Initial writing property: (Whether writing feeling, quick writing property, blurring property, ink density, etc. are normal)
2) Vibration blurring due to impact at knock return: (Scratch condition in round writing after impact)
3) Written wear resistance: (Amount of wear on the pen tip after mechanical writing until the end of writing, presence or absence of ball skipping)
4) Knock operability: (Is there any problem with reliable operation or shaking when carrying)
The four items were compared and evaluated under the same conditions with the number of samples n = 5.

Table 1 shows the contents of Examples 1 to 7 and Comparative Examples 1 to 5, and Table 2 shows evaluation results and calculated values.

By implementing the present invention, it is possible to solve the problems of writing, direct current, and backflow, etc., and in addition to writing tools that are easy to assemble and ballpoint pens with features such as thin and bold that are often requested by users, they are inexpensive and stable. Therefore, it is possible to solve the problem of wear durability such as scraping and ball jumping without adopting advanced ink or complicated shaft mechanism. In particular, the knock type has an effect of easily solving the problem of blurring caused by a collision at the time of return.

  A so-called neutral ballpoint pen that uses medium viscosity ink, which has many drawbacks in the past, has a structure in which a spring is built into the nib and the writing ball is always pushed forward to make close contact with the internal seal surface of the present invention. If the ink viscosity changes due to the shear force called pseudoplasticity in the ink, the viscosity is slightly high during storage, and the viscosity drops due to the shear force of the ball during writing. A great effect can be expected when used together. In addition, the present invention can obtain the same effect even when applied to a larger ball diameter, etc., and when used in combination with a backflow prevention mechanism such as a ball valve mechanism, the backflow can be prevented even under severe conditions such as writing upward. We can provide a writing instrument without problems.

FIG. 1 is a longitudinal sectional view showing the entire structure when the ballpoint pen is housed according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the entire structure when the ball-point pen tip protrudes according to the embodiment of the present invention. FIG. 3 is a longitudinal sectional view showing a ballpoint pen refill according to an embodiment of the present invention. FIG. 4 is an enlarged longitudinal sectional view showing the tip side structure of the ballpoint pen tip according to the embodiment of the present invention. FIG. 5 is a schematic view showing an outline (cam diagram) of a ballpoint pen knock rotating mechanism according to an embodiment of the present invention.

Explanation of symbols

1 ball
2 Caulking
3 inner walls
4 Channel groove
6 cradle
7 Ink hole
8 chips
9 Ink tube
10 Fitting
12 Elastic body
13 ink
17 Axis
18 Rear axle
21 Knock stick
25 Return spring

Claims (6)

The tip of the shaft has a tip hole through which the writing part can protrude, and the rear end has a knock bar that becomes a protruding pressing part. The rear end side is regulated by caulking at the rear end side by a receiving seat, and the inside has a pen tip having an ink hole for drawing ink from the rear end side, and the ink viscosity at normal temperature (23 ° C.). An ink storage tube that directly stores a so-called medium-viscosity ink in the range of 10 cp to 5000 cp, a channel groove that is configured by a plurality of grooves that communicate with the receiving seat and the ink holes, and that does not penetrate in the longitudinal direction, and a ball at the tip In a knock type ballpoint pen that has an elastic body that is placed so that it cannot be pulled out so that it is always pressed directly or between the movable members, and that contains a refill as a writing body inside the shaft so that it can move back and forth.
The relational expression: 20 · W <P <75 · W is satisfied between the projected area W (mm ² ) of the writing ball diameter and the pressing force P (g) of the elastic body in the nib, and the refill is always performed. It is configured to be urged rearward by a return spring, and there is a relational expression between the ball pressing force P (g) in the pen tip, the pressing force S (g) of the return spring, and the refill weight R (g). : A ballpoint pen characterized in that 50 · R <S <(50 · R + 20 · P) is satisfied.   In a knock-type writing instrument having a so-called double-knock type knock mechanism in which a knock stick is pressed to allow writing by projecting the writing body, and the knock stick can be pressed again to store the writing body. During the refill movement distance L from the time of protrusion to the non-written storage, the rotor that contacts the refill or the rear of the refill moves while rotating, and a part of the impact due to the return spring pressing force during storage is moved at a predetermined angle. 2. The ballpoint pen according to claim 1, wherein the ballpoint pen is converted into a rotational motion of θ and the relational expressions are 5 mm <L <10 mm and 40 degrees <θ <160 degrees.   In a knock-type writing instrument having a so-called double-knock type knock mechanism in which a knock stick is pressed to allow writing by projecting the writing body, and the knock stick can be pressed again to store the writing body. During the refill movement distance L from the time of protrusion to the storage of non-writing, the rotor that contacts the refill or the back of the refill moves while rotating, and a part of the impact due to the return spring pressing force during storage is moved at a predetermined angle. 2. The ballpoint pen according to claim 1, wherein the ballpoint pen is converted into a rotational motion of θ, and the relational expressions are 5 mm <L <10 mm and 40 degrees <θ <160 degrees.   There is a clip with elasticity on the outside of the shaft tube, and the writing part is projected so that it can be written by the engaging part of this clip, and when the clip is lifted to put the ballpoint pen on the clothes, the refill is automatically written In a knock-type ballpoint pen that has a so-called safety mechanism in which it is stored, all the parts that are separated in the writing state behind the refill and collide with each other at the time of return and receive impact are made of synthetic resin such as rubber, elastomer, plastic, etc. A material of which at least one of the parts has an internal loss η of 0.02 or more, which is a vibration absorbing performance, and an elastic modulus E that indicates rigidity of all the parts subjected to the impact is 1,300 MPa or more. The ballpoint pen according to claim 1, wherein the ballpoint pen is configured.   Refill which has a clip with elasticity on the outside of the shaft tube and makes the writing body projectably writeable by the locking portion of this clip and when the clip is lifted to put the ballpoint pen into clothes. In a knock-type ballpoint pen that has a so-called safety mechanism in which it is stored, all the parts that are separated in the writing state behind the refill and collide with each other at the time of return and receive impact are made of synthetic resin such as rubber, elastomer, plastic, etc. A material of which at least one of the parts has an internal loss η of 0.02 or more, which is a vibration absorbing performance, and an elastic modulus E that indicates rigidity of all the parts subjected to the impact is 1,300 MPa or more. 3. The ballpoint pen according to claim 2, wherein the ballpoint pen is configured.   There is a clip with elasticity on the outside of the shaft tube, and the writing part is projected so that it can be written by the engaging part of this clip, and when the clip is lifted to put the ballpoint pen on the clothes, the refill is automatically written In a knock-type ballpoint pen that has a so-called safety mechanism in which it is stored, all the parts that are separated in the writing state behind the refill and collide with each other at the time of return and receive impact are made of synthetic resin such as rubber, elastomer, plastic, etc. A material of which at least one of the parts has an internal loss η which is a vibration absorbing performance of 0.02 or more, and an elastic modulus E which indicates rigidity of all the parts subjected to the impact is 1,300 MPa or more. 4. The ballpoint pen according to claim 3, wherein the ballpoint pen is configured.

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